Safety device for hoisting mechanisms.



170. 777,661. I PATENTBD DEG. 20, 1904. W. BURKART & H. A. WILLIAMS. SAFETY 1137107; FOR norsrme MECHANISMS.

APPLICATION FILED MAY 14. 1904.

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No. 777,661. PATE'NTED DEC. 20, 1904. W. BURKART 8; H. A. WILLIAMS. SAFETY DEVICE FOR HOISTING MEGHANI3MS.

APPLICATION FILED MAY 14. 1904.

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UNITED STATES Patented December 20, 1904.

PATENT OEEIcE.

WILLIAM BURKART AND HARVEY A. WVILLIAMS, OF DENVER, COLORADO.

SPECIFICATION forming part of Letters Patent No. 777,661, dated December 20, 1904.

Application filed May 14, 1904. Serial No- 207,895.

To all, whom it may concern:

Be it known that we,WILLIAu BURKART and HARVEY A. WILLIAMS, citizens of the United States, residing at the city of Denver, in the county of Denver and State of Colorado, have invented or discovered new and useful 1mpro'vements in Safety Devices for Hoisting Mechanism, of which the following is a specification.

In the accompanying drawings, Figure 1 is a side elevation of a hoisting-cage fitted with our improved safety clutch mechanism, the same being shown in its inoperative position, the actuating mechanism being shown in dotted lines. Fig. 2 is an elevation of the upper part of said cage, showing the clutch mechanism in its operative position, the cover-plate and portions of the mechanism being shown in section. Fig. 3 is a side .view, partiallyin vertical section, of the same; and Fig. 4: is a partial plan view of the dogs, rock-shafts, and operating-lever shown in their operative position, the side of the cage and the draw-bar being shown in section.

Our invention relates to clutch mechanism for hoists of all kinds, more particularly that class of safety devices which normally when the hoist or cage is ascending and descending under control acts as the medium of connection between the hoisting mechanism and the cage, but in case the cable breaks or control is lost over the hoisting mechanism said clutch mechanism automatically engages guides fixed in the sides of the shaft and locks the cage in a stationary position.

Our invention consists in the peculiar construction of our clutching-dogs and their relative arrangement in connection with the various other portions of the cage structure. Our dogs are constructed of a substantially wedge shape and are also laterally beveled, so that when they engage the guides they tend to cut into and split the same, thereby wedging the split portion between the guide-shoes and the dogs, and thereby bringing the cage to an abrupt stop.

The following is a detailed description of the accompanying drawings:

1 is a hoisting-cage of any desired design or character, of which 2 is the floor, 2* the splash-boards, and 3 3 the uprights, extending up and securely fastened to side boards 4: 4:.

5 is the draw-bar yoke, securely fastened to side plates 1 4.

6 is the cover-plate, which is preferably attached to side plates 4 4 by means of eyes 7 7, integral with plate 4 4L, and eyebars 8 8, secured to cover plate 6, through which eyes pass rods 9, 9, thus securing the cover-plate 6 on each side to the adjacent side plate 4.

10 is an aperture through the center of the draw-bar yoke 5, the same being preferably reinforced by integral collar 11, surrounding said aperture 10, the cover-plate being cut away at 6 to surround said collar 11.

- 12 is a spacing-rod extending from one extremity of draw-bar yoke 5 to the other extremity thereof to stiffen the same.

13 13 are vertical guides, preferably of wood, fixed in the hoisting shaft or well and extending from bottom to top thereof.

14: 14 are the usual shoes fixed to cagel and adapted to slide on guides 13 13, thus steadying the cage in ascending or descending.

In the lateral faces of guides 13 13 we provide notches 15 15, spaced apart at any desired intervals and preferably of the contour shown, having horizontal bases.

16 16 are rock-shafts journaled in side plates 4 4 of the cage, as at 17 17.

18 18 are dogs or pawls rigidly attached to I the ends of rock-shafts 16 16 and adapted when turned toward each other, as in Fig. 2, to engage notches 15 15 in the guides 13 13.

19 19 are arms rigidly attached to rockshafts 16 16, preferably at their centers.

20 20 are links pivoted at lower ends to arms 19 19 and at their upper ends to wings 21 21 of nut 22, which engages the threaded extremity of d raw-bar 23. Said nut 22 is locked in place on draw-bar 23 by any convenient means, such as by pin 24 passing through a hole in said draw-bar below said nut 22 and a jam-nut 25 above nut 22. Said draw-bar 23 passes through aperture 10 in the draw-bar .yoke 5 and is provided at its upper end with a clevis 26, pivotally connected therewith, to which clevis 26 is attached the cable or other hoisting means. (Not shown.)

The draw-bar 23 is of such length and the parts so arranged and assembled that when the bar is drawn up until jam-nut 25 bears against the under side of draw-bar yoke 5 the dogs 18 18 are rotated out of engagement with notches 15 of the guides 13 13 and the cage is raised or lowered, being suspended by means of the draw-bar and cable, the weight of the cage being carried by the draw-bar. On the other hand, when said draw-bar 23 drops down, so that the clevis 25 rests on top of collar 11, the rock-shafts 16 16 are partially rotated, so that said dogs engage said notches and lock the cage in a stationary position in the shaft. Thus when tension is exerted by the hoisting-cable on clevis 26 in either hoisting or lowering the cage 1 the said cage is suspended by means of nut 25 bearing against the under face of draw-bar yoke 5, as shown in Fig. 1, the dogs being out of engagement with the notches in guides 13 13; but in case the cable breaks or the hoisting mechanism in any way fails to sustain the weight of the cage the tension is relieved from draw-bar 23, allowing it to drop, and thus partially rotating rock-shafts 16 16, thus immediately throwing the dogs 18 18 into engagement with notches 15 15 in guides 13 13, thus stopping the cage and locking it in a stationary position,

from which it can be released only by raising the draw-bar. 23 and rotating the dogs 18 18 out of engagement with said notches 15 15.

To aid the force of gravity in rotating said rock-shafts 16 16, we prefer to encircle each rock-shaft with a coiled spring 27, attached at its inner end to the rigid arm 19. The outer ends of said springs are fixed to spring-plate 29, which spans rock-shafts 16 16, said rockshafts freely turning in aperture 30 30 in said spring-plate 29. Said springs are so regulated that they act to resist the tension of the cable 26 and to rotate said pawls into engagement with said notches 15 15.

In constructing our dogs 18 18 we prefer to bevel the engaging portions of said dogs, as at 31 31, and construct them of the general wedge shape shown in the drawings, so that they will not bind or fail to engage the notches 15 15 through the rocking of the cage, but will tend to dig into the heart of the 'guides and if the rate of descent be sufiicient to accomplish it split the material of said guides so that the split portion will become wedged between the shoe and the dog, thus blocking the cage stationary.

From the above it is evident that our invention is an automatic and practically immediately acting means for locking a cage or hoistlng device of any description in a stationary position whenever the hoising-cable breaks or the hoisting mechanism fails to properly operate.

Although we have described the application of our invention with great minuteness for the sake of clearness, we do not wish to limit ourselves thereby, but claim, broadly 1. In hoisting mechanism, a cage, a rigid collar secured to said cage, a draw-bar adapted to move vertically in said collar, projections at the lower extremity of said draw-bar, links pivotally connected to said projections, rockshafts adjacent to the lower ends of said links, arms rigidly attached to said rock-shafts and pivotally secured to the lower extremities of said links, dogs rigidly secured to said rockshafts, coiled springs surrounding said rockshafts, one end of each of said springs being secured to a stationary member and the other ends of said springs being secured to said arms, for the purpose described.

2. In hoisting mechanism, a cage, a rigid collar secured to said cage, a draw-bar adapted to move vertically in said collar, a nut, having projections thereon, secured on the lower extremity of said draw-bar, links pivotally secured to said projections, rock-shafts adjacent to the lower ends of said links, arms rigidly attached to said rock-shafts and pivotally secured to the lower extremities of said links, dogs rigidly secured to said rock-shafts, coiled springs surrounding said rock-shafts, one end of each of said springs being secured to a stationary member and the other ends of said springs being secured to said arms, for the purpose described.

3. In hoisting mechanism, a cage, a rigid collar secured to said cage, a draw-bar adapted to move vertically in said collar, projections at the lower extremity of said draw-bar, links pivotally secured to said projections, rockshafts adjacent to the lower ends of said links, arms rigidly attached to said rock-shafts and pivotally secured to the lower extremities of said links, dogs rigidly secured to said rockshafts, a plate supported by said rock-shafts, coiled springs surrounding said rock-shafts, one end of each of said springs secured to said plate and the other ends of said springs secured to said arms, for the purpose described.

Signed at Denver, Colorado, this 25th day of April, 190&.

WILLIAM BURKART. HARVEY A. WILLIAMS.

Witnesses:

M. W. BARRETT, JOHN R. NEAL. 

